关键词： Selenium   Blood   Plasma   Urine   Toenail   Hair  

摘要： Biomonitoring is increasingly used to assess exposure to selenium (Se) in the population. However, there is little harmonization among protocols used in the different studies (varying biological matrices, differences in expression of results (concentrations versus amounts, units)). This makes inter-comparison of biomonitoring results across studies difficult. From a public health risk perspective, it also becomes challenging to estimate baseline levels in biological matrices for populations exposed by various sources. The aim of this study was thus to perform a systematic analysis of the relationship between Se intakes and biological concentrations based on published data. Inclusion and exclusion criteria were used and led to select 75 published biomonitoring data in humans from an extended review of Se biomonitoring studies. This represents 8 628 individuals who provided biological samples aiming at documenting Se exposure and/or Se concentrations in two or more biological matrices. Mathematical algorithms that relate Se intakes to biological concentrations and establish matrix-to-matrix associations were derived from these pooled biomonitoring data. Logarithmic regressions showed good correlations between Se intakes and whole blood concentrations (R-2 = 0.884), plasma concentrations (R-2 = 0.863) and urinary excretion rates (R-2 = 0.958). Blood and plasma concentrations were also strongly related (R-2 = 0.874), as were whole blood concentrations and urinary excretion rates (R-2 = 0.953). The interpretation of the log-regression coefficients allowed illustrating Se physiology. Se concentrations in plasma tend to plateau when daily intake exceed 150 mu g/d, whereas Se in urine increases rapidly above this threshold. The application of the algorithms to other independent data sets in order to reconstruct past Se intakes confirmed that interpretation of results on the basis of Se in integuments may be misleading if external contamination is not avoided. This approach

关键词： Physarum ploycephalum   Physarum-inspired model   ant colony optimization algorithms   travelling salesman problem  

摘要： Ant colony optimization (ACO) algorithms often fall into the local optimal solution and have lower search efficiency for solving the travelling salesman problem (TSP). According to these shortcomings, this paper proposes a universal optimization strategy for updating the pheromone matrix in the ACO algorithms. The new optimization strategy takes advantages of the unique feature of critical paths reserved in the process of evolving adaptive networks of the Physarum-inspired mathematical model (PMM). The optimized algorithms, denoted as PMACO algorithms, can enhance the amount of pheromone in the critical paths and promote the exploitation of the optimal solution. Experimental results in synthetic and real networks show that the PMACO algorithms are more efficient and robust than the traditional ACO algorithms, which are adaptable to solve the TSP with single or multiple objectives. Meanwhile, we further analyse the influence of parameters on the performance of the PMACO algorithms. Based on these analyses, the best values of these parameters are worked out for the TSP.

关键词： 模糊数学   评价算法   学生评教  

摘要： 针对传统评价算法的不足,笔者以模糊数学为基础,将边界不清的因素定量化,设计了一套新的评价算法。采用基于余弦相似度的思想,对模糊综合评价算法进行改进,并加入了"可信度"的计算,以控制人为的干扰因素,提高评价结果的可信度,为学生评教、教师评优等工作提供客观公正的评价数据,更好地为决策者提供支持。

关键词： polymer matrix   mechanical properties   composites   genetic algorithm  

摘要： The tensile, flexural, and impact properties of coir-fiber reinforced vinyl ester composites were evaluated. The short coir fibers with different proportions in fiber length and fiber content were used as reinforcements in polymer-based matrices. The mathematical models of tensile, flexural, and impact properties were developed using statistical packages and optimized using the genetic algorithm method to find the optimum fiber parameters for maximum value of mechanical properties.

关键词： 数学家   蛋糕   算法   设计   程序   福利   北京时间   研究成果  

摘要： [导读]在现实生活中，人们经常会遇到分蛋糕的问题，也就是如何实现公平、均分、毫无异议。 新浪科技讯 北京时间7月21日消息，据国外媒体报道，在现实生活中，人们经常会遇到分蛋糕的问题，也就是如何实现公平、均分、毫无异议。美国联合学院数学家朱利叶斯一巴拉巴内尔和纽约大学政治学者史蒂文一布拉姆斯近日在著名期刊《数学信使》上发表最新研究成果，声称可以完美解决公平分蛋糕问题。据了解，两位专家设计出一种最新算法，该算法可以有效地在两个人之间实现最理想的蛋糕均分，两分完全相等，任何一方都不会有吃亏的感觉。

关键词： 企业工资水平   宏观调控   评价   机制  

摘要： 随着我国经济进入加速转型期,市场机制在劳动力资源配置中作用不断加大,我国企业工资水平宏观调控体系机制已成为繁复的工程系统。本文运用广义数学期望算法构建企业工资水平宏观调控评价体系,从经济发展,社会和谐,生活协调三个方面对中国企业工资水平宏观调控体系展开综合评价,分析存在的问题,为优化和完善中国企业工资水平宏观调控机制提供决策依据和政策建议。

关键词： 教学改革   算法编程   案例驱动  

摘要： 针对当前数学类专业的计算机课程专业特点不突出的问题，提出以面向数学与计算机课程相结合的系列课程改革，并以数学方法编程课程为例，从教学内容、教学模式和考核手段等多方面进行阐述。经过近四年的教学实践验证，此次教学改革在提高学生的数学算法实现能力方面是比较成功的培养模式。

关键词： 高中数学   算法   信息技术   链接  

摘要： 本文从理解算法概念,提倡教学领悟;转变教师观念,提高教学能力;增加算法教学在计算机中的实际应用,以及鼓励学生在其他方面应用算法等方面,对促进高中数学中算法与信息技术链接的具体措施进行了讨论.

关键词： 线路舞动   数学模型   微元算法  

摘要： 为准确反映矿区35 kV供电线路舞动的情况,以中国平煤神马集团矿区35 kV及以下供电线路为研究对象,在输电线路舞动的三自由度动态数学模型的基础上,建立了基于分布参数微元算法的35 kV单导线输电线路舞动的数学模型。该模型的仿真计算结果与传统的输电线路舞动数学模型相比,更加准确,更能反映输电线路的真实舞动情况。

关键词： Algorithm   Neonatal sepsis   Preterm infants   Very low birth weight  

摘要： To study the diagnostic ability of RALIS (computerized mathematical algorithm and continuous monitoring device) to detect late onset sepsis among very low birth weight preterm neonates. Randomly chosen 24 very low birth weight infants with proven sepsis were compared to 22 infants without sepsis. The clinical parameters were retrospectively collected from the medical records. The ability of RALIS to detect late onset sepsis was calculated. RALIS positively identified 23 of the 24 infants with sepsis (sensitivity 95.8%). It indicated sepsis alert median 2.0 days earlier than clinical suspicion. A false positive alert was indicated in 23% (5/22) infants. The specificity, and positive and negative predictive ability of RALIS were 77.3%. 82.1% and 94.4%, respectively. RALIS may aid in the early diagnosis of late onset sepsis in very low birth weight preterm infants.